WECC Path Concept Task Force Report to PCC March 26, 2014 Chifong Thomas

2 Recap POTF New Paradigm and Potential Implication for Planning Next Steps Topics

3 The Path Concept White Paper was approved by the PCC and posted on the PCC Documents web site New PCC Path Concept Task Force was populated to continue work with the POTF Recap

4 Chuck Matthews (BPA) Jim Tucker (Deseret G&T) Abbas Abed (Navigant) Don Johnson (Portland General Electric) Gordon Dobson-Mack (Powerex) Brian Keel (SRP) Chifong Thomas (Smart Wire Grid) - Chair Rabi Kiran (SCE) David Franklin (SCE) Peter Mackin (USE) Bob Easton (WAPA-RMR) Branden Sudduth (WECC) Path Concept Task Force (PCTF)

5 To ensure that Facility Ratings and voltage limits are not exceeded in both the pre- and post-Contingency state To ensure that stability limits are not exceeded in the pre-Contingency state. Pre-Contingency stability limits are established to ensure pre- and post- Contingency BES stability. Ultimate reliability objectives

6 The “Path SOL” concept goes away: o While Facility Ratings and voltage limits pre- and post- Contingency are always SOLs, a Path itself does not have an SOL. The only time the Path itself has an SOL is when the Path happens to coincide with a monitored stability limit. o Instead, a Path has a Transfer Capability or Total Transfer Capability (TTC) as defined in the NERC Glossary of Terms Exceeding an established Transfer Capability or a TTC in real-time does not constitute SOL exceedance POTF Conclusions/Recommendations that can Impact Planning Processes

7 Operators should monitor actual Path flow against pre- determined TTC values to provide operator awareness of when reliability issues might be expected to occur WECC Path Ratings serve as a TTC cap for WECC Paths. TTC still needs to be determined: o Transfer analysis studies need to be run throughout the operations horizon to determine stability limits – even if voltage or thermal constraints are encountered at lower transfer levels Proposed to have agreements and understanding of who calculates TTC for every ATC Path in WECC. POTF Conclusions/Recommendations that can Impact Planning Processes

8 For TTC – Run transfer analysis studies ahead of time to determine the Path TTC. Allocates the Path TTC among TOPs who operate TTC Facilities on that WECC Path. For Reliability – Run transfer analysis studies ahead of time to determine stability limits and to identify thermal and voltage limitations that could be encountered. Changes in Operator Activities that can impact Planning Process

9 SOL exceedances (as indicated by real-time tools) to be mitigated by the most appropriate or effective means: With internal congestion management tools (CAISO and BPA have these), and/or Locally according to operational plans and procedures, or Op Guides, and/or With interconnection-wide congestion management tools administered by Peak RC. Changes in Operator Activities that can impact Planning Process

10 How do nomograms fit in to the new paradigm? Possible Solutions: o Nomograms determine TTC, not SOL. o TOP that identified flow interactions between two ATC paths needs to continue to coordinate on TTC establishment for those paths. Remaining Issue(s) that can Impact Planning Process

11 If Path Ratings are TTC caps, and nomograms determine TTCs o Can the real-time Path flow exceed the established Path Rating?  If so,  Should the potential exceedance be estimated ahead of real- time?  Should the TTC facility owner(s) be required to request a TTC exceedance?  How should impacts on other systems due to real-time TTC exceedance be accounted for?  How would the planner know when this happens and plan for system improvements? Questions for Planning Processes

12 o If a Path Owner requests to increase the seasonal or real-time Path TTC, would the Path Owner then be required to go through the Path Rating Process?  If not, what does it mean to have an Accepted Rating? o Other issues? Questions for Planning Processes

13 Identify issues and develop solutions Next Steps

Questions?